There are generally four main types of automotive drive line systems. More specifically, there exists a full time front wheel drive system, a full time rear wheel drive system, a part time four wheel drive system, and an all wheel drive system. Most commonly, the systems are distinguished by the delivery of power to different combinations of drive wheels, i.e., front drive wheels, rear drive wheels, or some combination thereof. In addition to delivering power to a particular combination of drive wheels, most drive systems permit the respectively driven wheels to rotate at different speeds. For example, the outside wheels must rotate faster than the inside drive wheels, and the front drive wheels must normally rotate faster than the rear wheels.
Drive line systems also include one or more Cardan (universal) and constant velocity joints (CVJ). Cardan joints are the most basic and common type joint used for example, in prop shafts. Although highly durable, Cardan joints are typically not suited for applications with high angles (e.g., greater than 2 degrees) because of their inability to accommodate constant velocity rotary motion. Constant velocity joints, in contrast, are well known in the art and are employed where transmission of a constant velocity rotary motion is desired or required. For example, a tripod joint is characterized by a bell shaped outer race (housing) disposed around an inner spider joint which travels in channels formed in the outer race. This spider shape cross section of the inner joint is descriptive of the three equal spaced arms extending therefrom which travel on the tracks of the outer joint. Part spherical rollers are featured on each arm.
One type of constant velocity universal joint is a plunging tripod type, characterized by the performance of end motion in the joint. Plunging tripod joints are currently the most widely used in-board (transmission side) joint in front wheel drive wheels, and particularly in the prop shafts found in rear wheel drive, all wheel drive and four wheel drive vehicles. A common feature of tripod universal joints is their plunging or end motion character. Plunging tripod universal joints allow the interconnection shafts to change length during operation without the use of splines which provoke significant reaction forces thereby resulting in a source of vibration and noise. Other common types of constant velocity joints are the plunging VL or cross groove type joint which consists of an outer race and inner race drivably connected through balls located in circumferentially spaced straight or helical grooves alternately inclined relative to a rotational axis. A high speed fixed joint is another type of constant velocity well known in the art and used where transmission of high speed is required. The disc style constant velocity fixed joint is another type of joint known in the prior art. This joint has an outer joint member open on both ends and a cage is assembled from the end opposite the end towards which the cage is urged by the ball expulsion forces under articulated load conditions. The prior art also includes a mono block constant velocity fixed joint also known as a mono block high speed fixed joint. The outer joint part is a bell shaped member having a closed end.
Drive line systems also include one or more ball spline joints which include a plurality of balls enclosed within a cage to permit rotation around inner and outer respective races. Like constant velocity joints, ball spline joints are adapted to accommodate plunge in the axial direction, i.e., end wise movement. However, unlike constant velocity joints, ball spline joints do not permit articulation at angle.
A typical drive line system incorporates one or more of the above joints in an all wheel drive or traditional four wheel drive system. In an all wheel drive systems, such joints are used to connect a pair of propeller shafts to a power take off unit and a rear driveline module, respectively. These propeller shafts function to transfer torque to the rear axle in rear wheel and all wheel drive vehicles. Similarly, in a traditional four wheel drive system, such joints are used to connect a propeller shaft between a transfer case and a front axle.
In the prior art there have been problems with the insertion and installation of a propeller shaft having a high speed fixed joint on one end and a VL plunging joint on the opposite end. The problem occurs when the shaft is installed into the vehicle backwards because both the high speed fixed joint and the VL plunging joint have the same outer diameter and bolt pattern (PCD). If the shaft is installed in the vehicle backwards, it may lead to damage of the VL plunging joint or the high speed fixed joint. Furthermore, the driveline system will not operate as designed if the prop shaft is installed backwards (incorrectly orientated).
Therefore, there is a need in the art to provide a propeller shaft having an in vehicle installation error proofing method to insure that the prop shafts are installed in the correctly aligned position within the driveline of the automotive vehicle. There also is a need in the art for an improved cover, including a mechanical stop to ensure proper installation of the prop shaft within the driveline of the automotive vehicle